You have nothing to worry about, you've got the range advantage, you've got the mobility advantage, and let's face it, you're talking to us so you've also got the tactics advantage
He'll try to press forward and shoot a lot. You can keep him away with quick tap shots, that probably won't hit him but it could discourage him from getting too close. I don't know about others, but when I have a high capacity blaster, I like to hold my trigger down to ensure I hit something. If he does this, he'll have a lot of repumping to do, get in close and hose him down while he does this. Repeat as necessary.